Environmental Question #42 [Wool Super Washing]

What are your thoughts on wool and the practice of super washing? Are there any brands you recommend if we are looking for safe wool? 

Courtesy of Reddit user u/Futt_Bucker_Fred  

What are your thoughts on wool and the practice of super washing? Are there any brands you recommend if we are looking for safe wool? 

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Thank you for asking this question! This is an area that I didn't know much about before and I had a lot of fun researching it, since textiles are an area of interest for me, but I haven't worked with wool before.

The short answer is that super washed wool is totally safe for you to wear, but it does also involve adding plastic to the wool.

The process involves two steps. The first step is bleaching the wool, then washing the bleach off. As far as safety is concerned we can ignore that step, because the bleach is washed off completely as part of that process. If the bleach wasn't totally washed off then it wouldn't be possible to dye the wool, and it would cause a rash on contact with your skin. Both of those are situations that the wool producers have a vested interest in avoiding, so we can be confident that they do a good job cleaning off the bleach.

The second step in super washing is coating the wool fibers in nylon (called Hercosett in the wool industry for some reason). The bleach used in the first step is chlorine bleach, which is why super washing is often also called the "Chlorine-Hercosett" process. The nylon forms a very thin and smooth coating that makes the wool smoother while helping to prevent it from fraying. Nylon is a synthetic, nonbiodegradable plastic, but as plastics go it's one of the better ones. It can be made biodegradable when manufactured in specific ways, and it isn't known to pose any toxicity to humans (although research on plastic toxicity is always still ongoing).

That said, having a nylon coating on your wool garment means there is a little bit of plastic in it, so it will biodegrade slower when it is thrown away, and some microplastics will be created as it breaks down. I absolutely understand if you want your wool to be plastic-free and all natural, but I wouldn't worry about the wool's safety either way. Almost all swimsuits are made almost entirely out of nylon, so there are hundreds of times more nylon in one swimsuit than in a super washed wool sweater.

I've never bought wool before, so I'm not sure what to look for to avoid super washing (I'm a big fan of cotton. I run hot and wool makes me itchy). I imagine that brands that don't super wash would want to brag about it though, so I'd probably look for brands that advertise stuff like "super wash free," "Hercosett free," "no plastic," "no nylon," "raw," "natural," "no superwash," or stuff like that.